#include <bits/stdc++.h>
using namespace std;

#ifndef ONLINE_JUDGE
#include <bits/debug.h>
#endif

#define int int64_t
#define endl "\n"

using PII = pair<int, int>;
using TII = tuple<int, int, int>;
template <class T> using V = vector<T>;
using i64 = long long;
using i128 = __int128;
using u64 = unsigned long long;

#define FOR(i, a, b) for (int i = (int)(a); i <= (int)(b); i++)
#define FOR2(i, a, b, c) for (int i = (int)(a); i <= (int)(b); i += (int)(c))
#define FORD(i, b, a) for (int i = (int)(a); i >= (int)(b); i--)
#define FORD2(i, b, a, c) for (int i = (int)(a); i <= (int)(b); i -= (int)(c))
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define lowbit(x) ((x) & (-x))
#define RE return;
#define Yes cout << "Yes" << endl;
#define YES cout << "YES" << endl;
#define No cout << "No" << endl;
#define NO cout << "NO" << endl;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define sz(x) (int)(x).size()

void solve() {
    int n, m;
    cin >> n >> m;

    V<V<int>> g(n + 1);
    V<int> d(n + 1, 0);

    FOR(i, 1, m) {
        int a, b;
        cin >> a >> b;
        g[a].eb(b);
        g[b].eb(a);
        d[a]++, d[b]++;
    }

    V<int> vis(n + 1, 0);

    queue<int> q;

    FOR(i, 1, n) {
        if (d[i] == 1) {
            q.push(i);
        }
    }

    while (sz(q)) {
        int t = q.front();
        q.pop();
        vis[t] = 1;
        for (auto& j : g[t]) {
            if ((--d[j]) == 1) {
                q.push(j);
            }
        }
    }

    int ans = 0, t = 0;
    function<void(int, int)> dfs = [&](int u, int fa) {
        if (vis[u])
            RE;
        vis[u] = 1;
        if (d[u] > 2) {
            t += (d[u] - 2);
            d[u] = 2;
        }
        for (auto& j : g[u]) {
            if (j == fa)
                continue;
            dfs(j, u);
        }
    };

    FOR(i, 1, n) {
        if (!d[i])
            continue;
        if (!vis[i]) {
            dfs(i, 0);
            ans++;
        }
    }

    cout << ans + t / 2 << endl;
}

signed main() {
    int Task = 1;

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    while (Task--) {
        solve();
    }

    return 0;
}
